LOCATION WESPAC CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Natrargids
TYPICAL PEDON: Wespac silt loam, rangeland, on a 1 percent slope under big sagebrush, greasewood, and basin wildrye at 4,005 feet elevation. (When described August 17, 1983, the soil was dry throughout. Colors are for dry soil unless otherwise noted).
A--0 to 4 inches; light brownish gray (10YR 6/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak very fine and fine platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine interstitial pores; moderately alkaline (pH 8.0) clear wavy boundary. (3 to 6 inches thick)
Bt--4 to 10 inches; light yellowish brown (10YR 6/4) silt loam, brown (10YR 4/3) moist; moderate very fine and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine vesicular pores; few thin clay films bridge mineral grains; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 6 inches thick)
Btn--10 to 19 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate very fine, fine and medium angular blocky; slightly hard, very friable, sticky and plastic; common very fine and few fine and medium roots; common very fine tubular pores; common thin clay films on peds and in pores; slightly effervescent with disseminated lime; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 14 inches thick)
Bnk--19 to 28 inches; very pale brown (10YR 7/3) loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine tubular pores; strongly effervescent, lime segregated in few fine soft filaments; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 10 inches thick)
C1--28 to 42 inches; pale yellow (2.5Y 8/2) loam, grayish brown (2.5Y 5/2) moist; weak medium platy structure; hard, friable, slightly sticky and slightly plastic; many very fine interstitial pores; ostracod shells present; violently effervescent with disseminated lime; moderately alkaline (pH 8.0); clear wavy boundary.
C2--42 to 60 inches; light gray (2.5Y 7/2) loam, olive brown (2.5Y 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; many very fine interstitial pores; violently effervescent with disseminated lime; moderately alkaline (pH 8.0).
TYPE LOCATION: Along the E boundary of the Sierra Army Depot, 1.0 miles N of Gate 443, 100 feet E of perimeter fence: 300 feet S and 100 feet E of the NW corner of section 9, T.27 N., R.17 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature varies from 53 to 56 degrees F. The thickness of the solum is 14 to 20 inches. These soils are dry in all parts of the moisture control section (6 to 19 inches) from June 1 to November 15 (167 days) and moist in all parts from December 1 to April 15. The soil temperature exceeds 41 degrees F from March 1 to December 1 (275 days) and exceeds 47 degrees F from April 15 to November 15.
The A horizon color is 10YR 5/3, 6/2 or 6/3. Moist color is 10YR 3/2 or 3/3. Texture is sand, fine sandy loam or silt loam. Reaction is mildly alkaline or moderately alkaline and noneffervescent to strongly effervescent.
The Btn horizon color is 10YR 5/4, 6/3, 6/4, 7/2 or 7/3. Moist color is 10YR 4/3, 4/4 or 5/4. Texture is clay loam or sandy clay loam with a weighted average of 27 to 35 percent clay and 35 to 50 percent sand. Reaction is moderately alkaline or strongly alkaline and slightly effervescent to violently effervescent. SAR ranges from 13 to 60. E.C. ranges from 4 to 8 mmhos.
The Bnk and C horizon colors are 10YR 6/3, 7/3; 2.5Y 7.2, 7/3 or 8/2. Moist colors are 10YR 4/3; 2.5Y 4/2, 4/3, 5/2, 5/4 or 5Y 4/3. Clay content ranges from 15 to 20 percent. Some pedons lack secondary filaments of gypsum and some pedons have C horizons with secondary carbonates. Sandy substratum phases are recognized that have stratified fine sand and sand 2C horizons at a depth of 30 to 60 inches. E.C. ranges from 8 to 16 mmhos and SAR ranges from 60 to 100.
COMPETING SERIES: These are the Antelope Springs, Calnat (T) and Slipback series. Antelope Springs soils have a mean annual soil temperature of 48 to 51 degrees F and have strongly or very strongly alkaline fine textured C horizons. Calnat soils are moderately deep to a paralithic contact. Slipback soils have 5 to 25 percent rock fragments in the control section, have 20 to 35 inch sola and are noneffervescent in the natric horizon.
GEOGRAPHIC SETTING: Wespac soils are on remnant lake terraces. Slopes are 0 to 2 percent. These soils formed in lacustrine sediments and reworked eolian beach deposits. Elevation is 4,000 to 4,050 feet. The climate is semi-arid with warm dry summers and cold somewhat moist winters. The mean annual precipitation is 6 to 12 inches. The mean annual temperature is 49 to 52 degrees F. The frost-free season is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Highrock and Mazuma soils. Mazuma soils are coarse-loamy. Highrock soils are dry for more than 200 days.
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow; slow permeability.
USE AND VEGETATION: Used as rangeland. The vegetation is big sagebrush, greasewood, and basin wildrye.
DISTRIBUTION AND EXTENT: Northeastern California, eastern Lassen County, in the Honey Lake Valley. The soils of this series are not extensive. MLRA 23, 27.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, California, Susanville Area Soil Survey Area, 2000. Date proposed: 1984.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from the surface to a depth of 10 inches (A, BAt horizons).
Natric horizon: The zone from 10 to 19 inches (Btn horizon).